Cognitively managed storage volumes for container environments

ABSTRACT

A method and system for pre-attaching volumes onto a host. The method includes analyzing a plurality of hosts in a cloud environment. The method also includes identifying a least populated host based on the analyzation of the hosts. The least populated host is based on the attributes of the hosts. The method also includes identifying at least one popular volume in the cloud environment. The popular volume is a volume type most frequently used by the hosts in the cloud environment. Further, the method includes attaching the popular volume to the least populated host.

BACKGROUND

The present disclosure relates to attachment of storage volumes tohosts, and more specifically, to a pre-attachment of storage volumes tohosts in a container-based environment.

Launching applications in a container-based environment, such as RedHat® (a trademarked product of Red Hat Software for providingopen-source software), OpenShift® (a trademarked product of Red HatSoftware for providing containerization software), or Docker® (atrademarked product of Docker for providing operating-system-levelvirtualization), is a routine operation that frequently occurs. Forexample, orchestrators can deal with hundreds, thousands, or evenmillions of containers each or which can launch and executeapplications. While many applications can operate utilizing onlyephemeral data, other applications, may require at least some of thedata to be persistent. Persistent data can be stored on storage volumesthat reside outside of the container environment. These storage volumescan be attached onto hosts and mounted to containers which theapplications can access and store persistent data.

SUMMARY

Various embodiments are directed to a method of pre-attaching popularvolumes to a host. The method can include analyzing a plurality of hostsin a cloud environment to determine various attributes of the hosts. Themethod can also include identifying a least populated host based onanalyzing the hosts. The least populated host can be based on theattributes of the hosts that were analyzed. The method can also includeidentifying at least one popular volume in the cloud environment basedon analyzing the hosts. The popular volume can be a volume type mostfrequently used by the hosts in the cloud environment. Further, themethod can include attaching the popular volume to the least populatedhost.

Various other embodiments directed to a method of pre-attaching popularvolumes on a host can further include identifying a least populated hostin a cloud environment by detecting a number of containers deployed onthe hosts. The method can also include determining a CPU usage of thehosts. The CPU usage can be a percentage of processing power used by thehosts. The method can include determining a memory usage of the hosts.The memory usage can be a percentage of total memory used by the hosts.Further, the method can include identifying a least populated host basedon the number of containers deployed, the CPU usage and the memory usageof the hosts.

Various other embodiments directed to a method of pre-attaching popularvolumes on a host can further include identifying at least one popularvolume by determining a plurality of volumes used in the cloudenvironment and ranking those volumes to develop a rank based onparameters of the volumes. The method can further include a rankthreshold based on the rank of the volumes to determine which volumes toattach to the least populated host. Further, the method can includeidentifying at least one popular volume that is ranked greater than therank threshold.

Additional embodiments are directed to a system, which can include atleast one processing component, at least one memory component, thememory component having program instructions which cause the processorto analyze a plurality of hosts in a cloud environment to determinevarious attributes of the hosts. The instructions can also cause theprocessor to identify a least populated host based on analyzing thehosts. The least populated host can be based on the attributes analyzedregarding the hosts. The instructions can also cause the processor toidentify at least one popular volume in the cloud environment based onanalyzing the hosts. The popular volume can be a volume type mostfrequently used by the hosts in the cloud environment. Further,instructions can also cause the processor to attach the popular volumeto the least populated host.

Further embodiments are directed to a computer program product fordeploying a workload on pre-attached hosts, which can include a computerreadable medium having program instructions therewith, the programinstructions executable by a processor to cause the device to executeinstructions. The instructions cause the device to receive a workload.The workload can include a workload volume list of at least one volumetype to be used by the workload. The device can also determine aplurality of available hosts and determine a plurality of availablepre-attached hosts. The pre-attached hosts can include a popular volumeattached to the pre-attached hosts. The popular volume can be a volumetype listed in the workload volume list. The device can also compare theavailable hosts to the pre-attached hosts and select a selected hostbased on the comparison. Further, the device can deploy the workloadonto the selected host.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the embodiments ofthe disclosure will become better understood with regard to thefollowing description, appended claims, and accompanying drawings where:

FIG. 1 is a diagram of a host system that connects multiple hosts to anorchestrator, according to embodiments of the present disclosure.

FIG. 2 is a flow diagram illustrating a process of deploying a workloadon a host system, according to embodiments of the present disclosure.

FIG. 3 is a flow diagram illustrating a process of determining a popularvolume, according to embodiments of the present disclosure.

FIG. 4 is a flow diagram illustrating a process of pre-attaching popularvolumes to hosts, according to embodiments of the present disclosure.

FIG. 5 is a flow diagram illustrating a process of detaching volumesfrom hosts, according to embodiments of the present disclosure.

FIG. 6 is a block diagram illustrating a cloud computing environment,according to some embodiments of the present disclosure.

FIG. 7 is a block diagram illustrating a set of functional abstractionmodel layers provided by the cloud computing environment, according tosome embodiments of the present disclosure.

FIG. 8 is a high-level block diagram illustrating an example computersystem that may be used in implementing one or more of the methods,tools, and modules, and any related functions, described herein, inaccordance with embodiments of the present disclosure.

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the particularembodiments described. On the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the scope ofthe disclosure Like reference numerals are used to designate like partsin the accompanying drawings.

DETAILED DESCRIPTION

In a container-based environment, mounting storage volumes typicallyrequires a multi-step process that involves Infrastructure as a Server(IaaS) interaction. First, a storage volume must be provisioned with anIaaS provider. Second, IaaS application programming interface (API) isused to discover the required endpoints. Third, the authorization andattachment occur on the requested host. Fourth, the volume is formatted,and finally the volume is mounted and ready for use. At least some ofthese steps must be repeated on every host using some type of storagevolume. This can create a slowdown when attempting to launch anapplication on a new host.

Also, applications have the ability to migrate from one host to anotheror can scale up or down depending on the situation. During migration,applications are typically rescheduled and restarted without utilizingor relying on any previous volumes or services provided by thepreviously used host. Restarting an application can also takes severalsteps such as, installing dependencies, allocating processor and memoryusage, as well as mounting any persistent volumes requested by theapplication.

Whether it be launching a new application, migrating an application, orrestarting an application, mounting a volume is a time-consumingprocess. The mounting process for a storage volume can generally take upto 60% of a total restart time when an application is first scheduledonto a host. Examples of storage volumes include NFS, Fibre Channel(FC), iSCSI, block storage, Glusterfs, GCEPeristentDisk, AzureFile, andmany others. It is common that applications may utilize volumes withvarying properties. These properties can include performance, size,speed, and access modes of the volume. Hence, a variety of volumes areoffered to cater to the specific needs of an application. Despite thevarying types of available storage volumes, the mounting processtypically remains the same. Thus, to alleviate some of the start-up timeof an application, embodiments of the disclosure pre-attach volumes ontohosts prior to a request by an application.

Disclosed herein are a method and a system for pre-attaching storagevolumes onto a host used for launching applications. The system cananalyze every host within an environment to determine which types ofvolumes are used and how many containers are deployed on each host. Onceanalyzed, the system can identify the least populated hosts as well asthe most frequently used volumes. After identifying the least populatedhosts and most frequently used volumes, the system can mount at leastone popular volume onto at least one of the least populated hosts. Thus,when an application is launched from a least populated host, the type ofvolume it requires may already be mounted to the host. This can decreasethe launch time of an application because the volume is pre-attached tothe host prior to the launch of the application.

FIG. 1 is a block diagram illustrating a host system 100, according toembodiments of the present disclosure. The host system 100 includes, butis not limited to, an orchestrator 110, hosts 120-1, 120-2, 120-N(collectively “host 120”), and a bus 130. The orchestrator 110 includesa host controller 112, a volume management system (“VMS”) 114, ascheduler 116, and a hook 118. The host 120 includes a container 122-1,122-2, 122-N (collectively “container 122”), a volume agent (“VA”)126-1, 126-2, 126-N (collectively “VA 126”), and a volume data collector(“VDC”) 128-1, 128-2, 128-N (collectively “VDC 128”). The orchestrator110 is communicatively coupled to the host 120 over the bus 130. Theoverall host system 100 is also communicatively coupled to a network 150over the bus.

The orchestrator 110 is a component of the host system 100 configured todetect and make decisions to events regarding the hosts 120. In someembodiments, the orchestrator 110 operates as a master node in aKubernetes® (a trademarked product of The Linux Foundation for managingcontainerized workloads and services) environment. Components of theorchestrator 110 can operate on hosts 120. For example, any host 120 canbe deemed as the orchestrator 110 to facilitate the needs of the hostsystem 100. However, for simplicity, all orchestrator 110 components arestarted on the same machine, and do not run applications. Typically, allinteractions with the hosts 120 operate through the orchestrator 110 andits various components. The orchestrator 110 is also configured to beresponsible for deciding what runs on the hosts 120. For example, theorchestrator 110 can schedule workloads, such as launching applications,as well as managing a workloads lifecycle, scaling, and upgrades. Theorchestrator 110 also manages network and storage resources for theworkloads.

The host controller 112 is a component of the orchestrator 110configured to execute decisions determined by the orchestrator 110. Insome embodiments, the host controller 112 is responsible for noticingand responding when a host is no longer operable, for maintaining thecorrect number of containers during replication, populates theendpoints, and creates default accounts and API access tokens. The hostcontroller 112 also interacts with the network 150 as needed. Forexample, the host controller 112 can check the network 150 to determineif a host has been deleted. The host controller 112 is also configuredto create, attach, and mount volumes and to interact with the network150 to arrange and direct the volumes.

The VMS 114 is a component of the orchestrator 110 configured to managethe volumes attached to the hosts 120. While shown as a separatecomponent in FIG. 1, it should be understood that the VMS 114 may bearranged as part of the host controller 112 or any other suitablecomponent of the host system 100, in some embodiments. The VMS 114 canmaintain data about how many containers are deployed on each host 120 inreal-time and the number of times each volume has been attached to thecontainers in the entire cloud. With that information, the VMS 114 candetermine which hosts 120 are the least populated on the network 150.The VMS 114 can also analyze the volume mounts on the network 150 andprepare and maintain a list of frequently used volumes, or “popular”volumes. In some embodiments, the VMS 114 utilizes the data it maintainsand decides which host 120 to pre-attach a volume to. For example, theVMS 114 can determine that an NFS volume is a popular volume and canpre-attach the NFS volume to a host 120.

The scheduler 116 is a component of the orchestrator 110 configured toassign which hosts run newly created or migrated containers. In someembodiments, the scheduler takes into account individual and collectiveresource requirements of the containers and hosts. For example, thescheduler 116 can identify a host 122 with available resources toaccommodate a newly launched container 122. Other factors, such aspolicy constraints, affinity and anti-affinity specifications, datalocality, inter-workload interference, and deadlines can also beconsidered by the scheduler 116 when determining which host 120 tolaunch a container 122 to.

The hook 118 is a component of the orchestrator 110 configured tointegrate the VMS 114 with the scheduler 116. While shown as a separatecomponent in FIG. 1, it should be understood that the hook 118 may bearranged as part of the host controller 112 or any other suitablecomponent of the host system 100, in some embodiments. The hook 118 isalso configured to provide an interface such that the VMS 114 cancommunicate with the scheduler 116 to provide additional host 120filtration and to narrow down the host 122 selection based on thepre-attached volumes. For example, the hook 118 allows the VMS 114 toreceive a list of hosts 120 from the scheduler 116 and to communicate arefined host list from the VMS 114 to the scheduler 116.

The host 120 is a component of the host system 100 configured to executeand run containerized applications and other workloads. Embodiments ofthe host 120 can also be performed as a node in a Kubernetes®environment or similar cloud environments. A host 120 can be a physicalmachine or a virtual machine (“VM”) depending on the configuration ofthe host system 100. Also, each host 120 can contain the necessaryservices to run containers as well the necessary components to bemanaged by the orchestrator 110.

The container 122 is a component of the host system 100 configured to bean executable package of software that runs applications. Includedwithin the container are code, runtime, system tools, system libraries,and settings. Multiple containers 122 can run on a single host 120 andare limited only by the resource limitations of the host. In someembodiments, multiple containers 122 are grouped together into containerclusters (e.g., Kubernetes® pods), that are deployed together andfunction as an interconnected whole.

The VA 126 is a component of the host system 100 configured to attachand detach volumes from the host 120. While shown as a separatecomponent in FIG. 1, it should be understood that the VA 126 may bearranged as part of the host 120 or any other suitable component of thehost system 100, in some embodiments. The VA 126 is deployed in everyhost 120 in the host system 100 and receives commands from the VMS 114regarding the volume details which it attaches locally to the node 120.For example, a VA 126 can mount the various volumes requested by thecontainer 122 and can also pre-attach volumes that are requested by theVMS 114.

The VDC 128 is a component of the host system 100 configured to sendinformation to the orchestrator 110 regarding volumes mounted to thehost 120. While shown as a separate component in FIG. 1, it should beunderstood that the VDC 128 may be arranged as part of the host 120 orany other suitable component of the host system 100, in someembodiments. Upon container deployment, the VDC 128 running on the node120 can fetch the volume details used by the container 122 and providethat information, as well as attached volume details, to the VMS 114.For example, a container 122 can be deployed on a host 120 that uses anNFS volume. The host 120 may also have an iSCSI volume attached. The VDC128 can report to the VMS 114 the volume information so that the VMS 114can utilize that information in making its determinations.

The bus 130 is a component of host system 100 configured to facilitatedirect, high-speed data transfers and communication between the host120, the orchestrator 110, and the network 150. In some embodiments, thebus 130 is an internal bus. In some other embodiments, the bus 130 is anexternal bus. Examples of the bus 130 include a LAN, a WAN, a FibreChannel (FC), and any combination thereof. In some embodiments,implementations interconnect together into many network configurationscapable of communicating over long distances. The bus 135 is configuredto transfer data utilizing a variety of standards. Some standardsinclude the Small Computer System Interface (SCSI), Fibre Channel, fiberconnection (FICON), and Internet Protocol (IP) standards.

The network 150 is a component of system 100 configured to facilitatedirect, high-speed data transfers and communication between the hosts120 and the orchestrator 110. In some embodiments, the network 150 is aninternal bus. In some other embodiments, the network 150 is an externalbus. Examples of the network 150 include a local area network (LAN), awide area network (WAN), a storage area network (SAN), intranet, or anycombination thereof.

FIG. 2 is a flow diagram illustrating a process 200 of deploying aworkload onto a host system 100, according to embodiments of the presentdisclosure. To illustrate process 200, but not to limit embodiments,FIG. 2 is described within the context of host system 100 of FIG. 1.Where elements described with respect to FIG. 2 are identical toelements shown in FIG. 1, the same reference numbers are used in bothFigures.

A scheduler 116 evaluates a workload and the hosts 120 operating withinthe host system 100 to determine which hosts 120 are available toreceive the workload. This is illustrated at step 210. A workload is anapplication or set of applications that can be containerized and can beindividually operated upon and executed. The workload can also includeprocesses, daemons, and batch jobs. The workload can be sent directly bya user, developer, administrator, or by any other means now known orlater developed. In a simplified example, the workload can includenumerous applications, batch jobs, and daemons along with otherinformation regarding how the workload is to be deployed. Once thescheduler 116 determines which hosts 120 are available, the scheduler116 can generate a list of possible hosts 120 to deploy the workload.For example, the scheduler 116 can generate a list that contains a host120-1 and host 120-2 that capable of receiving the workload. The hostlist generated by the scheduler 116 is then sent over to the VMS 114using the hook 118.

The VMS 114 analyzes the host list generated by the scheduler 114 todetermine if there is a corresponding host 120 that has a pre-attachedvolume that the workload requires. This is illustrated at step 230. Apre-attached host list can be maintained by the VMS 114 to compare withthe scheduler host list. To find an appropriate host 120, the VMS 114can analyze the workload to determine what type of volume is requiredfor deployment and then compare that requirement with the VMS host listto see if any hosts 120 have a pre-attached volume of the required type.For example, if the workload requires an iSCSI volume and host 120-2 hasan iSCSI volume pre-attached then the VMS 114 can notify the scheduler116 of that information.

To make the list comparison, the VMS 114 searches the VMS host list tomake a determination in finding a matching pre-attached host. This isillustrated at step 240. The VMS 114 can access a database to retrieve asuitable host 120. In some embodiments, the host database is updatedwhenever a host is used in a deployment, when a workload is deleted, andduring regular intervals. This allows the VMS 114 to maintain anup-to-date list of possible hosts 120 in such a way as to allow for anaccurate representation of pre-attached hosts 120. If a suitable host120 is located within the database, it can be used to deploy theworkload as illustrated at step 250.

However, if a pre-attached host 120 is not found and no host 120 has theappropriate pre-attached volume, the VMS 114 can prepare a suitable host120 for deployment. This is illustrated at step 260. In someembodiments, no pre-attach process occurs, and the scheduler selects ahost 120 for deployment. For example, if no host 120 has a pre-attachedvolume corresponding to the required volume of the workload, thescheduler 116 can then select any available host 120 as it deemsappropriate.

To prepare a suitable host 120, a host list can be sent forpre-attachment of the volume. In some embodiments, the suitable hostlist is a list maintained by the VMS 114. In some other embodiments, thesuitable host list is the scheduler host list. Once the suitable hostlist is received, the volume required by the workload can bepre-attached. The VA 126, from a host 120 on the suitable host list, canthen mount the volume required by the workload. If several volumes arerequired, each volume can be mounted to the host 120 prior to deploymentof the workload. Once mounted, the pre-attached host list can be updatedwith the corresponding information of the host 120. Information such aswhich type of volume was mounted, which host was utilized, and thenumber of applications can all be sent by the VA 126 to the VMS 114.

After the host 120 is pre-attached with the corresponding volume, theVMS 114 can return the selected host 120 back to the scheduler fordeployment of the workload. If no pre-attachment has occurred, the VMS114 can simply return the scheduler host list back to the scheduler 116.In some embodiments, several hosts 120 are sent to the scheduler 116which have the required volume(s) pre-attached. The scheduler 116 candeploy the workload on any of the hosts 120 returned by the VMS 114 asillustrated at step 270.

FIG. 3 is a flow diagram illustrating a process 300 of determiningpopular volumes for pre-attachment to hosts 120, according to someembodiments of the present disclosure. To illustrate process 300, FIG. 3is described within the context of host system 100 of FIG. 1.

A counter is initially set to allow for traversal of each volume used bythe host system 100. This is illustrated at step 305. Typically, thecounter is initially set to zero to allow a traversal of all thevolumes. However, the counter can be set to any pre-determined number toallow for partial traversal of the volumes.

After the counter is set, the volumes are ranked to determine whichvolumes to pre-attach and the counter is incremented. This isillustrated at step 310. A ranking of volumes can be based on a varietyof parameters. A parameter can be the total time duration that a volumewas in usage by a container 122. For instance, a volume may have aduration of 12 hours or 36 hours. The longer the duration, the morevalue the parameter gives to the volume. Another parameter may be thenumber of containers 122 that use a particular volume type. For example,a particular volume type can be mounted to twelve different containers122. The number of containers 122 utilizing a particular volume type canindicate that a volume is popular. Another example of a parameter can bevolume usage. A time window can be used to consider all volume usage(e.g., two days, one week, one month). During that time window, thevolumes that are used are ranked higher then those that are not. Theless usage or time that a volume has not be used, the lower the rank.Another parameter that can be used can be volume input/output (“I/O”)per interval. An interval of time can be set to determine the amount ofI/O that a volume type performs. The larger amount of I/O performed by avolume type can be used as an indicator of higher rank. The fewer I/Ooperations performed, the lower the rank of the volume. While these arejust a few examples of possible parameters, this is not intended to bean exhaustive list and any parameter can be used to determine volumeranking.

In one embodiment, the volumes are ranked according to:

$\begin{matrix}{{R({vol})} = \frac{\sum\limits_{i = 1}^{n}\; {{V({pi})} \times {W({pi})}}}{n}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

Parameters, such as the example parameters listed above, can be used inEquation 1 where each parameter pi is given a value V and a weight W.The weight can dictate which parameter is of higher importance incalculating the ranking of the volumes. For example, the total number ofcontainers parameter may have a higher weight than the volume usageparameter. The types of parameters used, and the weight of eachparameter can be altered and adjusted as an administrator sees fit. Thesummation of each value of parameter V(pi) multiplied by the weight ofthe parameter W(pi) is calculated and then divided by the total numberof parameters n. The result of which is used a rank R for the particularvolume vol. Once the rank is calculated, the counter is incremented.

A determination is made by process 300 as to whether the counter is lessthan the total number of volumes to be ranked. This is illustrated atstep 315. If the counter is less than the total number of volumes, step310 is repeated until all the volumes are ranked and the counter isincremented to overcome the restriction. However, if the counter is notless than the total number of volumes, then the process 300 proceeds tostep 320.

A rank threshold is calculated to determine which volumes to considerfor pre-attachment. This is illustrated at step 320. The volume with arank greater than the threshold can be considered for pre-attachment.This allows for a limited number of volumes to be selected forpre-attachment so that the host system 100 is not overwhelmed and thehosts 120 are not encumbered with unnecessary pre-attachments. Forexample, a threshold can be set such that only the top three rankedvolumes are selected for pre-attachment. An administrator can adjust thethreshold as necessary to correspond to the needs of the host system100.

In one embodiment, the rank threshold is determined according to:

$\begin{matrix}{T = \frac{\sum\limits_{i = 1}^{n}\; {R({Vi})}}{n}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

Where Vi is the volume of i, where R(Vi) is the rank of volume Vi, andwhere the total number of volumes is indicated as n. The rank thresholdcan be re-calculated at regular intervals dynamically or can be set byan administrator to run when a condition is met. For example, when aworkload is deployed or when a workload is deleted. In some embodiments,the volume ranks are calculated using Equation (1). However, otherranking equations can also be used to determine the rank threshold.

The counter is reset back to the starting number set at step 305. Thisis illustrated at step 325. Depending on which volumes are to be ranked,the counter is set and reset. In some embodiments, the counter is resetto zero. This allows for the specified volumes to be ranked and utilizedby the rank threshold.

A determination is made by the process 300 to see whether the rank ofthe volume exceeds the rank threshold. This is illustrated at step 330.Each volume is evaluated and if the rank of the volume exceeds the rankthreshold then that volume is considered as a popular volume. However,if the volume rank does not exceed the rank threshold, then the volumeis not considered as a popular volume.

If the volume rank is greater than the rank threshold, the process 300proceeds to step 335. A volume popularity list can be updated toindicate that the volume is considered popular. In some embodiments, adatabase is maintained with the popularity information as it isdetermined. However, if the volume is not greater than the rankthreshold, the process 300 proceeds to step 340. The volume popularitylist can be updated to indicate and keep track of which volumes are notconsidered popular and should be pre-attached to hosts 120. As with thepopular volumes, a database can be maintained with a list of unpopularvolumes.

After both step 335 and 340, the process 300 proceeds by incrementingthe counter. This is illustrated at step 345. In order to evaluate eachvolume, the counter is incremented to allow the process 300 to cyclethrough each volume rank.

A determination is made by process 300 to see whether the counter isless than the total number of volumes. This is illustrated at step 350.If the counter is determined to be less than the total number ofvolumes, the process 300 returns to step 330. However, if the counter isnot less than the total number of volumes, then process 300 is completeand the volumes have been ranked and evaluated with the rank threshold.

FIG. 4 is a flow diagram of a process 400 of pre-attaching popularvolumes to hosts 120 associated with a host system 100, according tosome embodiments of the present disclosure. In some embodiments, thepopular volumes are determined using the process illustrated in FIG. 3.However, other approaches can be used to identify popular volumes.

A counter is initially set to allow for traversal of each volume used bythe host system 100. This is illustrated at step 305. Typically, thecounter is set to zero to allow a traversal of all the volumes.

The host controller 112 retrieves a host 120 for pre-attachment ofpopular volumes. This is illustrated at step 410. In some embodiments, ahost 120 with the most available resources is retrieved. For example,hosts 120 can be evaluated to determine which host 120 has the fewestcontainers 122 or which host 120 has done the least amount of work overa period of time. Different evaluations can be conducted to determinewhich hosts 120 to retrieve. The VDC 128 located on each host 120 canupdate the VMS 114 with the host 120 information to allow for adetermination to be made as to which host 120 to retrieve.

Once the host 120 is retrieved, the volumes are inspected to determinewhether they are considered popular and thus eligible forpre-attachment. This is illustrated at step 415. In some embodiments,process 300 is triggered to evaluate the volumes so that process 400 canproceed with the pre-attachment process. The volumes considered aspopular can be pre-attached to the host 120. The VMS 114 can check thepopularity list generated by process 300 in making the determination. Ifthe volume is considered popular, the process 400 proceeds to step 420.However, if the volume is not considered popular, the process 400proceeds to step 425.

The VMS 114 instructs the VA 126 to pre-attach the volume onto the host120. This is illustrated at step 420. The VA 126, tasked withpre-attaching volumes of the host 120, checks to see whether the volumeis already attached to the host 120. If the volume is already attached,the VA 126 need not reattach the volume. However, if the volume is notattached to the host 120, then the VA 126 attaches the volume. The VDC128 provides the VMS 114 with which volumes are attached to the host 120and the VA 126 can also use that information in deciding whether thevolume needs attachment or if it is already attached.

This pre-attachment of volumes process proceeds for each popular volume.To cycle through each volume, the counter is incremented. This isillustrated at step 440. The counter is checked to determine whether ornot it is less than the total number of volumes as illustrated at step445. If the counter is less than the total number of volumes, theprocess 400 proceeds back to step 415 to analyze the next volume.However, if the volume count is not less the total number of volumes,then process 400 proceeds to step 450.

If a volume being analyzed at step 415 is not a popular volume, the VA126 determines whether the volume is already attached to the host. Thisis illustrated at step 425. An active host 120 may have several volumesattached and mounted to several operating containers 122. If a volume isnot attached to a host 120, the process 400 can proceed to step 440.However, if a volume is attached, the process proceeds to step 430 todetermine whether the volume is in-use by the containers 122 within thehost 120.

Containers 122 deployed in the host 120 are scanned to determine whetherthe volume is in-use by any of the containers 122. This is illustratedat step 430. Containers may request volumes to be attached and mountedas needed by an application. When the application no longer requires thevolume, the VA 126 can detach the volume from the host. This isillustrated at step 435. The detachment of volumes allows a host to beunencumbered from the volume and frees available resources the volumemay have been using. However, if a volume is still in-use, regardless ofwhether or not it is a popular volume, the VA 126 will keep the volumemounted and proceed to step 440 to evaluate the next volume.

Once all the volumes are evaluated on the retrieved host 120, theprocess waits a pre-determined time before another host is selected forthe pre-attachment process 400. This is illustrated at step 450. In someembodiments, a triggering event occurs that reinitiates thepre-attachment process 400. For example, while process 400 is waiting, aworkload deployment may be received which can trigger a pre-attachmentof a host 120. The wait time can be adjusted as an operator sees fitsuch that the process it utilized in an efficient manner.

FIG. 5 is a flow diagram of a process 500 for detaching volumes from ahost 120, according to the present disclosure. A workload deletionrequest is received by the orchestrator 110 to delete a particularworkload operating on some host 120. This is illustrated at step 510. Aworkload deletion can include deletions of applications with persistentdata, applications without persistent data, batch jobs, daemons, or anyprocess that may be operating on a host 120. The deletion request can bereceived by an operator who is managing the workload, an administratorof the host system 100, or the deletion request can be triggered after apredetermined time of operation.

Once the deletion request is received, the VMS 114 initiates thedetachment of volumes that correspond to the workload. This isillustrated at step 520. A workload may have been utilizing severalvolumes which may no longer be needed by the host 120. The VDC 128 cantransmit volume information of the workload back to the VMS 114 so thatthe volumes can be analyzed and determined whether they should bedetached from the host 120. Popular volumes, as determined by process300 in FIG. 3, can remain attached to the volume for later use.Unpopular volumes, not in use, can be detached which can conserveresources.

The VMS 114 analyzes the volume used by the deleted workload todetermine whether the volume is a popular volume. This is illustrated atstep 530. In some embodiments, the popular volume is determined by theprocess 300, where parameters are used to determine an overall rank ofthe volumes used in the host system 100. Also, the process 300 can beinitiated upon a workload deletion to determine a rank of the volumescurrently in use. If the volumes being analyzed is not considered apopular volume, the VA 126 can detach the volume from the host 120 ifthe volume is not in use by any other workload or application. However,if the volume is considered a popular volume, the volume is not detachedfrom the host 120 and the process concludes.

In some embodiments, the processes of pre-attachment of volumesdescribed herein could be implemented in a cloud computing environment,which is described below with respect to FIGS. 6, 7, and 8. It is to beunderstood that although this disclosure includes a detailed descriptionon cloud computing, implementation of the teachings recited herein arenot limited to a cloud computing environment. Rather, embodiments of thepresent invention are capable of being implemented in conjunction withany other type of computing environment now known or later developed.

Cloud computing is a model of service delivery for enabling convenient,on-demand network access to a shared pool of configurable computingresources (e.g., networks, network bandwidth, servers, processing,memory, storage, applications, virtual machines, and services) that canbe rapidly provisioned and released with minimal management effort orinteraction with a provider of the service. This cloud model may includeat least five characteristics, at least three service models, and atleast four deployment models.

Characteristics are as follows:

On-demand self-service: a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded automatically without requiring human interaction with theservice's provider.

Broad network access: capabilities are available over a network andaccessed through standard mechanisms that promote use by heterogeneousthin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to servemultiple consumers using a multi-tenant model, with different physicaland virtual resources dynamically assigned and reassigned according todemand. There is a sense of location independence in that the consumergenerally has no control or knowledge over the exact location of theprovided resources but may be able to specify location at a higher levelof abstraction (e.g., country, state, or datacenter).

Rapid elasticity: capabilities can be rapidly and elasticallyprovisioned, in some cases automatically, to quickly scale out andrapidly released to quickly scale in. To the consumer, the capabilitiesavailable for provisioning often appear to be unlimited and can bepurchased in any quantity at any time.

Measured service: cloud systems automatically control and optimizeresource use by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active user accounts). Resource usage can bemonitored, controlled, and reported, providing transparency for both theprovider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer isto use the provider's applications running on a cloud infrastructure.The applications are accessible from various client devices through athin client interface such as a web browser (e.g., web-based e-mail).The consumer does not manage or control the underlying cloudinfrastructure including network, servers, operating systems, storage,or even individual application capabilities, with the possible exceptionof limited user-specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer isto deploy onto the cloud infrastructure consumer-created or acquiredapplications created using programming languages and tools supported bythe provider. The consumer does not manage or control the underlyingcloud infrastructure including networks, servers, operating systems, orstorage, but has control over the deployed applications and possiblyapplication hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to theconsumer is to provision processing, storage, networks, and otherfundamental computing resources where the consumer is able to deploy andrun arbitrary software, which can include operating systems andapplications. The consumer does not manage or control the underlyingcloud infrastructure but has control over operating systems, storage,deployed applications, and possibly limited control of select networkingcomponents (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for anorganization. It may be managed by the organization or a third party andmay exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by severalorganizations and supports a specific community that has shared concerns(e.g., mission, security requirements, policy, and complianceconsiderations). It may be managed by the organizations or a third partyand may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the generalpublic or a large industry group and is owned by an organization sellingcloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or moreclouds (private, community, or public) that remain unique entities butare bound together by standardized or proprietary technology thatenables data and application portability (e.g., cloud bursting forload-balancing between clouds).

A cloud computing environment is service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure that includes anetwork of interconnected nodes.

FIG. 6 is a block diagram illustrating a cloud computing environment600, according to some embodiments of the present disclosure. As shown,cloud computing environment 600 includes one or more cloud computingnodes 610 with which local computing devices used by cloud consumers,such as, for example, personal digital assistant (PDA) or cellulartelephone 620-1, desktop computer 620-2, laptop computer 620-3, and/orautomobile computer system 620-4 may communicate. Nodes 610 maycommunicate with one another. They may be grouped (not shown) physicallyor virtually, in one or more networks, such as Private, Community,Public, or Hybrid clouds as described hereinabove, or a combinationthereof. This allows cloud computing environment 600 to offerinfrastructure, platforms and/or software as services for which a cloudconsumer does not need to maintain resources on a local computingdevice. It is understood that the types of computing devices 620-1-620-4shown in FIG. 6 are intended to be illustrative only and that computingnodes 610 and cloud computing environment 600 can communicate with anytype of computerized device over any type of network and/or networkaddressable connection (e.g., using a web browser).

FIG. 7 is a block diagram illustrating a set of functional abstractionmodel layers 700 provided by the cloud computing environment 600,according to some embodiments of the present disclosure. It should beunderstood in advance that the components, layers, and functions shownin FIG. 7 are intended to be illustrative only and embodiments of theinvention are not limited thereto. As depicted, the following layers andcorresponding functions are provided:

Hardware and software layer 710 includes hardware and softwarecomponents. Examples of hardware components include: mainframes 711;RISC (Reduced Instruction Set Computer) architecture-based servers 712;servers 713; blade servers 714; storage devices 715; and networks andnetworking components 716. In some embodiments, software componentsinclude network application server software 717 and database software718.

Virtualization layer 720 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers721; virtual storage 722; virtual networks 723, including virtualprivate networks; virtual applications and operating systems 724; andvirtual clients 725.

In one example, management layer 730 provides the functions describedbelow. Resource provisioning 731 provides dynamic procurement ofcomputing resources and other resources that are utilized to performtasks within the cloud computing environment. Metering and Pricing 732provide cost tracking as resources are utilized within the cloudcomputing environment, and billing or invoicing for consumption of theseresources. In one example, these resources may include applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.User portal 733 provides access to the cloud computing environment forconsumers and system administrators. Service level management 734provides cloud computing resource allocation and management such thatrequired service levels are met. Service Level Agreement (SLA) planningand fulfillment 735 provide pre-arrangement for, and procurement of,cloud computing resources for which a future requirement is anticipatedin accordance with an SLA.

Workloads layer 740 provides examples of functionality for which thecloud computing environment can be utilized. Examples of workloads andfunctions that can be provided from this layer include: mapping andnavigation 741; software development and lifecycle management 742;virtual classroom education delivery 743; data analytics processing 744;transaction processing 745; and determining causes of events in datasets 746.

Referring now to FIG. 8, shown is a high-level block diagram of anexample computer system 801 (e.g., devices 105, server 135, device 205,retention enhancement system 201) that may be used in implementing oneor more of the methods, tools, and modules, and any related functions,described herein (e.g., using one or more processor circuits or computerprocessors of the computer), in accordance with embodiments of thepresent disclosure. In some embodiments, the major components of thecomputer system 801 may comprise one or more CPUs 802, a memorysubsystem 804, a terminal interface 812, a storage interface 816, an I/O(Input/Output) device interface 814, and a network interface 818, all ofwhich may be communicatively coupled, directly or indirectly, forinter-component communication via a memory bus 803, an I/O bus 808, andan I/O bus interface unit 810.

The computer system 801 may contain one or more general-purposeprogrammable central processing units (CPUs) 802-1, 802-2, 802-3, and802-4, herein generically referred to as the CPU 802. In someembodiments, the computer system 801 may contain multiple processorstypical of a relatively large system; however, in other embodiments thecomputer system 801 may alternatively be a single CPU system. Each CPU802 may execute instructions stored in the memory subsystem 804 and mayinclude one or more levels of on-board cache.

System memory 804 may include computer system readable media in the formof volatile memory, such as random-access memory (RAM) 822 or cachememory 824. Computer system 801 may further include otherremovable/non-removable, volatile/non-volatile computer system storagemedia. By way of example only, storage system 826 can be provided forreading from and writing to a non-removable, non-volatile magneticmedia, such as a “hard-drive.” Although not shown, a magnetic disk drivefor reading from and writing to a removable, non-volatile magnetic disk(e.g., a “floppy disk”), or an optical disk drive for reading from orwriting to a removable, non-volatile optical disc such as a CD-ROM,DVD-ROM or other optical media can be provided. In addition, memory 804can include flash memory, e.g., a flash memory stick drive or a flashdrive. Memory devices can be connected to memory bus 803 by one or moredata media interfaces. The memory 804 may include at least one programproduct having a set (e.g., at least one) of program modules that areconfigured to carry out the functions of various embodiments.

One or more programs/utilities 828, each having at least one set ofprogram modules 830 may be stored in memory 804. The programs/utilities828 may include a hypervisor (also referred to as a virtual machinemonitor), one or more operating systems, one or more applicationprograms, other program modules, and program data. Each of the operatingsystems, one or more application programs, other program modules, andprogram data or some combination thereof, may include an implementationof a networking environment. Programs 828 and/or program modules 830generally perform the functions or methodologies of various embodiments.

In some embodiments, the program modules 830 of the computer system 801may include a retention enhancement module. The retention enhancementmodule can be configured to obtain user data for a user currentlyreading electronic text on a device, analyze the user data to determinewhether a retention action should be issued, and execute a retentionaction in response to a determination that the retention action shouldbe issued.

Although the memory bus 803 is shown in FIG. 8 as a single bus structureproviding a direct communication path among the CPUs 802, the memorysubsystem 804, and the I/O bus interface 810, the memory bus 803 may, insome embodiments, include multiple different buses or communicationpaths, which may be arranged in any of various forms, such aspoint-to-point links in hierarchical, star or web configurations,multiple hierarchical buses, parallel and redundant paths, or any otherappropriate type of configuration. Furthermore, while the I/O businterface 810 and the I/O bus 808 are shown as single respective units,the computer system 801 may, in some embodiments, contain multiple I/Obus interface units 810, multiple I/O buses 808, or both. Further, whilemultiple I/O interface units are shown, which separate the I/O bus 808from various communications paths running to the various I/O devices, inother embodiments some or all of the I/O devices may be connecteddirectly to one or more system I/O buses.

In some embodiments, the computer system 801 may be a multi-usermainframe computer system, a single-user system, or a server computer orsimilar device that has little or no direct user interface but receivesrequests from other computer systems (clients). Further, in someembodiments, the computer system 801 may be implemented as a desktopcomputer, portable computer, laptop or notebook computer, tabletcomputer, pocket computer, telephone, smart phone, network switches orrouters, or any other appropriate type of electronic device.

It is noted that FIG. 8 is intended to depict the representative majorcomponents of an exemplary computer system 801. In some embodiments,however, individual components may have greater or lesser complexitythan as represented in FIG. 8, components other than or in addition tothose shown in FIG. 8 may be present, and the number, type, andconfiguration of such components may vary.

The present disclosure may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent disclosure.

The computer readable storage medium is a tangible device that canretain and store instructions for use by an instruction executiondevice. Examples of computer readable storage media can include anelectronic storage device, a magnetic storage device, an optical storagedevice, an electromagnetic storage device, a semiconductor storagedevice, or any suitable combination of the foregoing. A non-exhaustivelist of more specific examples of the computer readable storage mediumincludes the following: a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), a static randomaccess memory (SRAM), a portable compact disc read-only memory (CD-ROM),a digital versatile disk (DVD), a memory stick, a floppy disk, amechanically encoded device such as punch-cards or raised structures ina groove having instructions recorded thereon, and any suitablecombination of the foregoing. A computer readable storage medium, asused herein, is not to be construed as being transitory signals per se,such as radio waves or other freely propagating electromagnetic waves,electromagnetic waves propagating through a waveguide or othertransmission media (e.g., light pulses passing through a fiber-opticcable), or electrical signals transmitted through a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network can comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers, and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present disclosure may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present disclosure.

Aspects of the present disclosure are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of thepresent disclosure. It will be understood that each block of theflowchart illustrations and/or block diagrams, and combinations ofblocks in the flowchart illustrations and/or block diagrams, can beimplemented by computer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general-purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present disclosure. In this regard, each block in theflowchart or block diagrams may represent a component, segment, orportion of instructions, which comprises one or more executableinstructions for implementing the specified logical function(s). In somealternative implementations, the functions noted in the block may occurout of the order noted in the figures. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently, or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration but are not intended tobe exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdisclosed herein.

Although the present disclosure has been described in terms of specificembodiments, it is anticipated that alterations and modification thereofwill become apparent to the skilled in the art. Therefore, it isintended that the following claims be interpreted as covering all suchalterations and modifications as fall within the true spirit and scopeof the present disclosure.

1-9. (canceled)
 10. A system, comprising: a processor; a memory to storeinstructions, which when executed from the memory, cause the processorto perform operations on the system, analyzing a plurality of hosts on anetwork to determine various attributes of the hosts; identifying aleast populated host based on analyzing the plurality of hosts, whereinthe least populated host is identified based on the attributes of thehosts; selecting at least one popular volume on the network based on theanalyzation of the hosts, wherein the popular volume is identified as avolume type most frequently used by the hosts on the network; attachingthe popular volume to the least populated host; and detaching at leastone unpopular volume from the least populated host, wherein the at leastone unpopular volume is based on a volume popularity list.
 11. Thesystem of claim 10, wherein the least populated host is based on afewest number of containers deployed on at least one of the hosts on thenetwork.
 12. The system of claim 10, wherein identifying at least onepopulated host on a network, comprises: detecting a number of containersdeployed on the hosts; determining a CPU usage for the hosts, whereinthe CPU usage is a percentage of processing power used by the hosts;determining a memory usage for the hosts, wherein the memory usage is apercentage of total memory used by the hosts; and selecting a leastpopulated host based on the number of containers deployed, the CPUusage, and the memory usage of the hosts.
 13. The system of claim 10,wherein identifying at least one popular volume comprises: determining aplurality of volumes used on the network; ranking the volumes to developa rank based on parameters of the volumes; determining a rank thresholdbased on the rank of the volumes to determine which volumes to attach tothe least populated host; and identifying at least one popular volumethat is ranked greater than the rank threshold.
 14. The system of claim13, wherein a rank threshold is a summation of the ranks for the volumesdivided by a total number of volumes on the network.
 15. The system ofclaim 13, wherein the parameters include a container usage amount, inwhich volume container usage amount indicates a number of containersutilizing each of the volumes.
 16. (canceled)
 17. The system of claim10, wherein detaching at least one popular volume comprises: triggeringan initiation event, wherein the initiation event prompts adetermination of least popular volumes on the least populated host;determining at least one mounted volume on the least populated host;determining whether the mounted volume with the popular volume is a sametype as the popular volume; and upon determining that the mounted volumeis not the same type as the popular volume, detaching the mountedvolume.
 18. A computer program product for deploying pre-attached hosts,the computer program product comprising a computer readable storagemedium having program instructions embodied therewith, the programinstructions executable by a processor to cause the processor to:receive a workload, the workload includes a workload volume list of atleast one volume type to be used by the workload; determine a pluralityof available hosts; determine a plurality of available pre-attachedhosts, the pre-attached hosts include a popular volume attached to thepre-attached hosts, wherein the popular volume is identified as a volumetype most frequently used on a network; compare the available hosts tothe pre-attached hosts; selecting a selected host based upon thecomparison of the available hosts to the pre-attached hosts; and deploythe workload on the selected host.
 19. The computer program product ofclaim 18, wherein the popular volume comprises instructions to:determine a plurality of volumes used on the network; rank the volumesto develop a rank based on parameters of the volumes; determine a rankthreshold based on the rank of the volumes to determine which volumes toattach to the least populated host; and identify at least one popularvolume that is ranked greater than the rank threshold.
 20. The computerprogram product of claim 19, wherein a rank threshold is a summation ofthe ranks for the volumes divided by a total number of volumes on thenetwork.